1. Field of the Invention
The present invention relates to a method for preparing a patterned metal oxide layer or a patterned metal layer by using a solution of a metal oxide precursor or a metal precursor and, more particularly, to a method for preparing a patterned carrier transport layer of a solar cell or a patterned biomedical material.
2. Description of Related Art
Currently, the patterning methods used to form nano-patterns can be e-beam lithography, ion-beam lithography, DUV (deep ultraviolet)/EUV (extreme ultraviolet) photolithography, soft X-ray lithography, and nanoimprint lithography. Among the aforementioned patterning techniques, the nanoimprint technique has advantages of high resolution, high throughput, and low cost, so it is widely applied in various fields.
The dye-sensitized solar cell has the advantages of simple processing and low production cost, and can be formed on a flexible substrate, so, many researches have been undertaken to improve the photoelectric conversion efficiency of the dye-sensitized solar cell, in order to apply the dye-sensitized solar cell into various fields. In the structure of the dye-sensitized solar cell, a TiO2 layer on the electrode has good electron conductivity. Hence, after dyes absorb light and transfer photons into charges, the TiO2 layer can increase the probability of transporting the charge to an external circuit, and thereby the photoelectric conversion efficiency of the dye-sensitized solar cell can be improved. However, the structure and the morphology of the TiO2 layer may influence the transport of the electrons, and may further influence the photoelectric conversion efficiency of the dye-sensitized solar cell.
The nano-scaled TiO2 possesses large surface-to-volume ratio, and the photoelectric conversion efficiency of the dye-sensitized solar cell can be improved when the nano-scaled TiO2 is used. Hence, various types of nano-scaled TiO2 have been developed, such as TiO2 nanoparticles, TiO2 carbon nanotubes, and TiO2 nanocrystals. The spin-coated TiO2 nanoparticle layer just has a plane-structure. If the plane-structure of the TiO2 nanoparticle layer can be patterned to form 3D structure, the reaction areas of the TiO2 layer can be increased, and the photoelectric conversion efficiency of the dye-sensitized solar cell can also be improved.
In addition, titanium and an alloy thereof have excellent biocompatibility and have been widely applied to biomedical researches and bio-implants such as bone plates and bone screws. Furthermore, TiO2 not only can be used as anti-bacterial material, but also can be applied to medical treatments, such as angiopathy treatments.
In order to increase the reactivity of the implants, a sandblasting process can be performed to roughen the surfaces of the bio-implants. However, the roughness of the surfaces cannot be controlled properly when the sandblasting process is performed. Hence, it is desirable to provide a method for forming patterns on the surfaces of the bio-implants to control the roughness and the morphology of the surfaces, and wherein it is possible to increase the bioactivity of the implants through the designed patterns.